Aortic aneurysm is a recently increasing disease. One-fourth of aneurysms occur thoracically and three-fourth thereof occur abdominally. It is reported that 0.7 to 4.2% of the population are affected by the disease. Ruptured aneurysm has a mortality rate of 80 to 90%, which is very high, with the life-saving rate being 50% even when a trip to hospital by ambulance and surgery are successfully carried out. According to the Population Survey Report in Japan in 2012, aortic aneurysm, together with aortic dissection, is the 9th leading cause of death among females (7517 deaths/1.3%).
Cases of aneurysms having expanded diameters have been conventionally treated by blood vessel prosthesis implantation. Recently, however, a less invasive stent graft therapy replaces blood vessel prosthesis implantation and becomes rapidly prevalent. The principle and object of the therapy is to implant a stent graft at a relatively normal site of the vessel which is at a centre or periphery of an aortic aneurysm to block blood flow into the wall of the aortic aneurysm, thereby eliminating the pressure and preventing a fatal event such as aortic aneurysm rupture.
However, a huge issue of stent graft-related complications has been recognised even in large-scale clinical studies in Europe and the United States such as migration in which a stent graft is displaced from the implanted site late after implantation and endoleak in which blood flows into an aortic aneurysm through the gap between a stent graft and the vessel where the stent graft is implanted. According to the report from the Japanese Committee for Stentgraft Management, among 3124 cases of abdominal aortic aneurysm treated with stent grafts between 1 Jul. 2006 to 31 Dec. 2008, endoleak (16.8%) and migration (0.1%) were identified.
Preventing the stent graft-related complications is thus an urgent problem to be addressed. In order to solve the problem, research has been carried out to devise the methods including addition of basic fibroblast growth factor (bFGF) to a stent graft, as disclosed in the following Non Patent Literatures 1 to 3.
For example, a bFGF-releasing stent graft is reported in Non Patent Literature 1 that is prepared by impregnating a stent graft impregnated with collagen and heparin with a bFGF solution.
In Non Patent Literature 2, a bFGF-releasing stent graft is prepared by impregnating a stent graft with 10% water-soluble elastin and 0.5% heparin sodium salt followed by impregnation with 2 μg/mL bFGF solution.
In Non Patent Literature 3, a stent graft is prepared that is coated with an N-rich plasma-polymerised thin film (a thin ethylene film onto which a compound for promoting migration, adhesion and proliferation of cells comprising a high amount of nitrogen molecules such as amines, imines and nitriles is plasma-polymerised) serving as a scaffold for cells and promoting migration thereof.
However, none of the documents discloses an internal regenerating factor production-inducing agent, and HGF, VEGF, SDF-1, EGF, IGF-1, G-CSF and the like as an internal regenerating factor.
Meanwhile, Patent Literatures 1 and 2 disclose coating agents respectively comprising a stent or the like coated with an endogenous repair factor production-promoting agent such as PGI2 (IP) agonist, EP2 agonist and EP4 agonist. However, the agents are for prevention of restenosis of, for example, the coronary artery and are not for prevention of stent graft-related complications (migration and endoleak) which are to be addressed by the present invention.
Therefore, the present invention is totally novel over the background art and is not suggested by the background art.